An emergency department visit may triple the risk of respiratory and GI infections for nursing home residents, researchers found.

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The study found an emergency department visit may triple the risk of respiratory and gastrointestinal infections for nursing home residents.

Note that in the presence of an ongoing outbreak of influenza or other infection at the care facility, a visit to the emergency department had no additional effect on risk.

An emergency department visit may triple the risk of respiratory and gastrointestinal infections for nursing home residents, researchers found.

The rate of new acute respiratory or GI infections was 5% within a week of an emergency department visit compared with 2% when not leaving the long-term care facility, according to Caroline Quach, MD, of McGill University in Montreal, and colleagues.

After adjustment for other factors, seniors at such facilities were 3.9-fold more likely to acquire an infection following a trip to the emergency department, the group reported online in CMAJ.

Whether patients are picking up pathogens in the waiting room or exam room -- from staff or other patients -- additional precautions may be reasonable for five to seven days after their return from the emergency department, Quach's group recommended.

"If they acquire an infection while in the emergency department, these residents may be the source of an outbreak upon return to their facility," they wrote.

If that does happen, the consequences can be substantial, the investigators noted.

"Prolonged length of stay, limited capacities for diagnosis, and variable infection control programs may allow outbreaks to propagate and persist for many months, underlining the importance of identifying potential sources of infectious agents," they added.

One prior study suggested that an influenza outbreak would kill almost one patient in 100 in a nursing home and incur more than $6,000 in costs over 30 days.

Quach's study examined outcomes at 22 nursing homes in Ontario and Quebec during the months of September 2006 to May 2008 when a trip to the emergency department would most likely result in cold, flu, and gastroenteritis exposure.

Among the 1,269 residents included in the study, 424 visited the emergency department during these periods.

The incidence of new respiratory or GI infections was 8.3 per 1,000 patient-days among those who visited the emergency department compared with 3.4 per 1,000 patient-days among those who did not (P=0.007).

Those who went to the emergency department, not surprisingly, were sicker with more comorbidities (P<0.001). More of those patients also had visitors (47% versus 39%, P=0.01), who could have exposed them to infection.

Adjustment for these and other factors did not eliminate the statistical significance of the association between the emergency department and acquired infections, but rather boosted the odds ratio from 2.5 to 3.9.

In the presence of an ongoing outbreak of influenza or other infection at the care facility, a visit to the emergency department had no additional effect on risk.

The researchers noted that nursing homes typically have surveillance programs for outbreaks, which could have led to detection bias if residents who went to the emergency department were monitored more closely or their symptoms documented more often.

But emergency department visits weren't considered a risk factor at the time, so this likely wasn't an important source of bias, the group suggested.

They also pointed to retrospective chart review and lack of data on the duration of emergency department visits as study limitations.

The study was supported by the Canadian Patient Safety Institute, the Quebec Ministry of Health, and the Canadian Institutes for Health Research.

Quach reported receiving consultancy fees from Novartis for studying meningococcal group B vaccine and grant support from Merck Frosst for studying nosocomial rotavirus infections and from GlaxoSmithKline (GSK) for studying the effectiveness of a monovalent rotavirus vaccine in children.